Infusion device having offset flow path

ABSTRACT

An infusion device, including: a housing; an infusion cannula extending downwardly away from the housing and capable of receiving an insertion needle; a septum disposed in the housing; a passageway under said septum and in fluid communication with said cannula; and, an infusion needle insertable through the septum, the infusion needle capable of penetrating the septum and entering said passageway thereby forming a flow path between the infusion needle and the infusion cannula and wherein the infusion cannula and the infusion needle are aligned on separate non identical axes.

RELATED APPLICATION

[0001] This application claims priority under 35 U.S.C. Section 119 toU.S. Provisional Application No. 60/459,252 entitled Device ForSubcutaneous Medication Using An Offset Flow Path, filed on Mar. 31,2003, the complete disclosure of which is incorporated herein byreference in its entirety for all purposes.

TECHNICAL FIELD

[0002] The present invention is related to infusion devices, includinginsulin or other medication infusion devices that are positioneddirectly on a patient's skin.

BACKGROUND OF THE INVENTION

[0003] Numerous medication infusion devices which sit directly on top ofa patient's skin have been developed. Such devices typically operate asfollows. A housing of the device is placed on the patient's skin suchthat an infusion cannula (extending downwardly therefrom) piercesthrough the patient's skin. Typically, the housing is placed against thepatient's skin by use of an inserter needle assembly. Specifically, aninsertion needle on the inserter needle assembly is received through thehousing, passing through the center of the infusion cannula. The mainbody of the inserter needle assembly is then used to press down againstthe housing, pushing the housing down against the patient's skin whilethe inserter needle guides the infusion cannula into the patient. Then,the inserter needle assembly is removed, pulling the inserter needle outof the housing, and leaving the hollow infusion cannula in the patientfor delivery of medication therethrough. Then, a connecting hub istypically attached onto the housing. Fluid medication is then infusedinto the connecting hub, passing sequentially through the housing andthe infusion cannula and into the patient. Examples of such systems arefound in U.S. Pat. Nos. 6,056,718 and 6,685,674.

[0004] As can be seen, a problem common to these systems is that boththe inserter needle and an infusion needle (in the connecting hub) passthrough the septum in the same location. This is due to the fact that inexisting designs, the infusion cannula, inserter needle, and infusionneedle are all co-linear with one another.

[0005] A disadvantage of this common design is that the septum must bepierced in the same location by both the inserter needle (which isremoved after the housing is placed onto the patient's skin) and theinfusion needle (which passes through the septum when the connecting hubis attached to the housing). Re-using the same location in the septumfor two different needle entries has the potential for causing septumwear and leakage. As will be further explained herein, otherdisadvantages of such “in-line” designs also exist.

SUMMARY OF THE INVENTION

[0006] The present invention provides an infusion device, having: ahousing; an infusion cannula extending downwardly away from the housingand capable of receiving an insertion needle; a septum disposed in thehousing; a passageway under said septum and in fluid communication withsaid cannula; and, an infusion needle insertable through the septum, theinfusion needle capable of penetrating the septum and entering saidpassageway thereby forming a flow path between the infusion needle andthe infusion cannula and wherein the infusion cannula and the infusionneedle are aligned on separate non identical axes. Such axes may beparallel, in different planes relative to one another or at obliqueangles relative to one another. The infusion needle is positioned topenetrate the septum thereby forming a flow path between the infusionneedle and the infusion cannula when the connecting hub is attached tothe housing.

[0007] In accordance with the present invention, the infusion cannulaand the infusion needle are disposed off-axis to one another. Forexample, the infusion cannula and the infusion needle may be positionedparallel to one another. In preferred embodiments, the infusion needleis disposed in the center of the connecting hub and the infusion cannulais disposed off-center in the housing; however, the present invention isnot so limited.

[0008] In accordance with the present invention, the infusion needle (inthe connecting hub) passes through the septum at a location differentfrom where an insertion needle (in the infusion cannula) passes throughthe septum. An advantage of this design is that there is significantlyreduced potential for leakage since the insertion needle (used toinitially position the infusion cannula in the patient) passes throughthe septum at a location different from the location where the infusionneedle passes through the septum.

[0009] A further advantage of the present invention is that inembodiments where the infusion needle is positioned at the center of theconnecting hub, the connecting hub can be rotatable with respect to thehousing. This gives the patient greater comfort and flexibility since aninfusion tube extending from the connecting hub can be rotated todifferent radial positions, as desired. As will be explained, thepresent connecting hub can be rotatable with respect to the housingthrough a full 360 degrees, some through amount less than 360 degrees,or alternatively, not be rotatable at all.

[0010] Another advantage of the present invention is that there is notorque on the infusion cannula when the connecting hub is rotated. Thisis particularly advantageous since the infusion cannula is received intothe patient. Torque on the infusion cannula would cause irritation tothe patient.

[0011] Another advantage of the present invention is that the infusionneedle and infusion cannula may be of different diameters. Thus,different connecting hubs having different diameter infusion needles(e.g.: with different flow rates therethrough) can be interchangeablyused with a single housing sitting on the patient's skin.

[0012] Another advantage of the present invention is that, by placingthe infusion needle and the infusion cannula parallel to one another,the overall height of the assembled device can be reduced as compared tothat of a standard “in-line” co-linear design.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a sectional side elevation view of the presentinvention, prior to attaching the connecting hub onto the housing.

[0014]FIG. 2 is a sectional side elevation view of the present inventionwith the connecting hub attached to the housing.

[0015]FIG. 3 is a bottom plan view of the lower portion of the housingof the present invention.

[0016]FIG. 4 is a top perspective view of the present invention, showingthe connecting hub with flexible handles attached thereto.

[0017]FIG. 5 is a bottom perspective view of the present invention withthe adhesive bandage removed.

[0018]FIG. 6 is a bottom exploded perspective view of the housing of thepresent invention.

[0019]FIG. 7 is a top exploded perspective view of the housing of thepresent invention.

[0020]FIG. 8 is a bottom exploded perspective view of the connecting hubof the present invention.

[0021]FIG. 9 is a top exploded perspective view of the connecting hub ofthe present invention.

[0022]FIG. 10 is a sectional side elevation view of the housing with apositioning needle assembly sitting thereon, with a positioning needlereceived through the infusion cannula.

[0023]FIG. 11 is a bottom exploded perspective view of the positioningneedle assembly.

[0024]FIG. 12 is a top exploded perspective view of the positioningneedle assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

[0025] The present invention provides an infusion device having an“offset” design in which an infusion cannula (which is received into apatient's skin) is not co-linear with an infusion needle (which extendsfrom a removable connecting hub), as follows:

[0026] Referring first to FIG. 1, an infusion device 10 is provided.Infusion device 10 includes a housing 100 which is positioned against apatient's skin. Specifically, an adhesive bandage 150 extends outwardlyfrom housing 100 and an infusion cannula 110 extends downwardly awayfrom housing 100. Infusion cannula 110 pierces through the patient'sskin when adhesive bandage 150 is affixed to the patient's skin. Aseptum 120 is disposed within housing 100. In the illustratedembodiment, septum 120 is disposed between lower portion 140 and upperportion 130; however, the present invention is not so limited.

[0027] A connecting hub 200 is also provided. Connecting hub 200includes a main body 220 and an infusion needle 210 extending downwardlytherefrom, and a pair of flexible handles 230. As can be seen, infusionneedle 210 is preferably co-linear with axis 300. (In the illustratedembodiment, axis 300 passes through the center of both connecting hub200 and housing 100). As can therefore be seen, infusion cannula 110 isnot co-linear with axis 300.

[0028] Connecting hub 200 is configured to be attached by a userdirectly on top of housing 100. This is seen clearly in FIG. 2. Tosecurely connect connecting hub 200 onto housing 100, flexible handles230 may be used. In the illustrated embodiment, each of flexible handles230 includes a tab 231 which is received into a small notch 135 formedbetween lower portion 140 and upper portion 130.

[0029] When connecting hub 200 is attached on top of housing 100 (asshown in FIG. 2), infusion needle 210 penetrates septum 120 therebyforming a flow path 400 between infusion needle 210 and infusion cannula110, in the preferred embodiment being a lateral passageway. As will beexplained herein, infusion needle 210 is preferably in fluidcommunication with an infusion tube connected to the side of connectinghub 200, to supply medication infusion therethrough. Because cannula 110is on one axis and the infusion needle 210 is along another axis and notcollinear, it is possible for the entire body to be shallower than ifthe two axes were aligned. The preferred arrangement has the needle 210and cannula parallel but in different planes. They need not be parallel.The infusion needle could be inserted at an angle off vertical (such asan oblique angle), so long as it reaches the passageway (flow path) 400so that fluid communication therebetween can occur.

[0030] A further advantage of the design shown in FIG. 2 is thatconnecting hub 200 may be freely rotatable with respect to housing 100even after connecting hub 200 has been attached to housing 100. This isbecause infusion needle 210 is preferably positioned in the center ofdevice 10 (i.e.: co-linear with axis 300) and because tabs 231 may befreely moveable along through notch 135 (which runs around housing 100between upper and lower portions 130 and 140 respectively). As a result,connecting hub 200 may freely rotate to different radial positions withrespect to housing 100 since connecting hub 200 simply rotates aroundcentrally-located infusion needle 210 while tabs 231 slide around withinnotch 135 around the perimeter of housing 100. In optional embodiments,stops (not shown) may be positioned around notch 135 to limit rotationof connecting hub 200 with respect to housing 100. As a result, thepresent invention is understood to encompass embodiments whereinconnecting hub 200 is fully rotatable 360 degrees with respect tohousing 100, or rotatable less than 360 degrees with respect to housing100, or wherein connecting hub 200 is not rotatable with respect tohousing 100 at all. Consequently, the present invention encompassesembodiments wherein connecting hub 200 is attachable to housing 100 atdifferent rotational positions.

[0031]FIG. 3 shows a bottom plan view of lower portion 140 of housing100. The offset distance 350 between infusion cannula 110 and infusionneedle 210 is clearly seen. In such preferred embodiments, infusioncannula 110 and infusion needle 210 are positioned parallel to oneanother. In most preferred embodiments, infusion needle 210 is disposedin the center of connecting hub 200 (i.e.: along axis 300) and theinfusion cannula 110 is disposed off-center to the housing (i.e. notalong axis 300); however, the present invention is not so limited.

[0032]FIG. 4 shows a top perspective view of main body 220 of connectinghub 200. Flexible handles 230 are also seen. Connecting hub 200 furtherincludes a side infusion port 225. An infusion tube 215 (FIG. 9)connected into infusion port 225 is in fluid communication with infusionneedle 210. Thus, fluid entering connecting hub 200 through infusionport 225 passes directly through infusion needle 210, and then throughseptum 120, across flow path 400, and then down through infusion cannula110, and into the patient.

[0033] In preferred embodiments, infusion cannula 110 and infusionneedle 210 may have different diameters. It is to be understood,therefore, that the present invention encompasses embodiments whereinfusion cannula 110 is either larger or smaller in diameter thaninfusion needle 210, and also encompasses embodiments where infusioncannula 110 has the same diameter than infusion needle 210.

[0034]FIG. 5 shows further details of the bottom of assembled infusiondevice 10.

[0035]FIGS. 6 and 7 shows the narrowed distal end 111 of infusioncannula 110, which minimizes discomfort to the patient when infusioncannula 110 pierces the patient's skin. FIG. 6 also shows furtherdetails of septum 120. Specifically, an insertion needle 510 (FIGS. 10to 12) passes through septum 120 at location 121; whereas infusionneedle 210 passes through septum 120 at location 122.

[0036]FIGS. 8 and 9 show further details of connector hub 200 andflexible handles 230. As shown in FIG. 9, a fluid infusion tube 215 maybe connected into infusion port 225. Thus, fluid introduced intoinfusion port 225 by fluid infusion tube 215 will pass out of infusionneedle 210.

[0037]FIG. 10 shows an insertion needle assembly 500 which is used forpositioning housing 100 against the patient's skin. Insertion needleassembly 500 includes an insertion needle 510 which is initiallypositioned to extend through infusion cannula 110, passing throughseptum 120 at location 121, as shown.

[0038] Insertion needle assembly 500 further includes a handle assembly520. The patient typically uses a spring loaded inserter (not shown)that advances handle assembly 520 thereby pressing housing 100 downwardagainst their skin such that infusion cannula 110 and insertion needle510 together pierce through the patient's skin. Such downward motioncontinues until adhesive bandage 150 is pressed firmly against thepatient's skin. Then, the spring loaded inserter (not shown) is removed,and handle 520 is pulled upwardly by the patient away from their skin,thus pulling insertion needle 510 out of infusion cannula 110. Theremaining hollow infusion cannula 110 is then used to infuse medicationinto the patient. Once the needle 510 is removed, that passagewaytherethrough is no longer required. Instead infusate will pass throughthe offset infusion needle 210 across the lateral flow path 400 and intocannula 110.

[0039]FIGS. 11 and 12 show further details of insertion needle assembly500.

[0040] In an alternate embodiment of the present invention, the septumis instead positioned in the connecting hub and the infusion needle isinstead disposed in the housing. In such embodiment, the flow pathbetween the infusion needle and the infusion cannula is within theconnecting hub, not within the housing.

[0041] In an alternate embodiment, septum 120 is pre-slit and infusionneedle 210 comprises a hollow tube, which may optionally be made ofplastic.

[0042] The present invention also encompasses a method of infusing fluidinto a patient, by: positioning an infusion housing 100, having apassageway 400, against a patient's skin, such that an infusion cannula110 extends downwardly away from the infusion housing 100 penetrates thepatient's skin along a first axis, thereby providing a pathway forinfusate into the patient; and inserting an infusion needle 210 intohousing 100 along an axis 300 adjacent, but not identitical with saidfirst axis; and causing infusate to pass through insertion needle 210,into passageway 400 and then into infusion cannula 110.

What is claimed is:
 1. An infusion device, comprising: a housing; aninfusion cannula extending downwardly away from the housing and capableof receiving an insertion needle; a septum disposed in the housing; apassageway under said septum and in fluid communication with saidcannula and; an infusion needle insertable through the septum, theinfusion needle capable of penetrating the septum and entering saidpassageway thereby forming a flow path between the infusion needle andthe infusion cannula and wherein the infusion cannula and the infusionneedle are aligned on separate non identical axes.
 2. The device ofclaim 1, wherein the infusion cannula and the infusion needle arepositioned parallel to one another.
 3. The device of claim 1, whereinthe infusion cannula and the infusion needle are positioned parallel toone another.
 4. The device of claim 1, wherein the infusion cannula andthe infusion needle are in different planes relative to each other. 5.The device of claim 1, wherein the infusion cannula and the infusionneedle are at oblique angles relative to each other.
 6. The device ofclaim 1, wherein the infusion needle is disposed in the center of theconnecting hub and the infusion cannula is disposed off-center to thehousing.
 7. The device of claim 1, wherein the infusion cannula and theinfusion needle have different diameters.
 8. The device of claim 1,wherein the connecting hub is rotatable with respect to the housing. 9.The device of claim 8, wherein the connecting hub is rotatable 360degrees with respect to the housing.
 10. The device of claim 8, whereinthe connecting hub is rotatable less than 360 degrees with respect tothe housing.
 11. The device of claim 1, wherein the connecting hub isattachable to the housing at different rotational positions.
 12. Thedevice of claim 1, wherein the connecting hub further comprises: atleast one flexible handle configured to attach the connecting hub ontothe housing.
 13. The device of claim 1, wherein the housing furthercomprises: an adhesive bandage extending therefrom for holding thehousing against the patient's skin.
 14. The device of claim 1, whereinthe connecting hub further comprises: a fluid infusion tube extendingfrom the connecting hub, the fluid infusion tube being in fluidcommunication with the infusion needle.
 15. The device of claim 1,wherein the septum is pre-slit and wherein the infusion needle is aplastic tube.
 16. A method of infusing fluid into a patient, comprising:positioning an infusion housing, having a passageway, against apatient's skin, such that an infusion cannula extends downwardly awayfrom the infusion housing penetrates the patient's skin along a firstaxis, thereby providing a pathway for infusate into the patient; andinserting an infusion needle into the housing along an axis adjacent,but not identitical with said first axis; and causing infusate to passthrough said insertion needle, into said passageway and then into saidinfusion cannula.
 17. The method of claim 16, wherein the passageway inhe infusion housing is a lateral passageway.